A particularly important national need exists for enhancing safety and security of environments ranging from residential structures, to subways, to airports, and to borders. Chemical warfare agents are 1 of the major threats to homeland security. Research that leads to a clear path for the development of low cost, fast, rugged, and extremely sensitive sensors for real-time monitoring is of high demand to homeland security. The goal of this research proposal is to develop extremely sensitive and highly selective microsensors for chemical warfare agents or simulants by using enzyme based layer-by-layer nanoassembly modified microcantilevers. The aim of the phase I of this project is to validate the feasibility of our technology for ultimate fabrication of microcantilever sensor devices. [unreadable] The specific aims include: (1) fabrication of a microchannel fluid cell, (2)Surface modification of microcantilevers, (3)Thermodynamic study. The ultimate goal in phase II will be to develop a handhold mierocantilever arrays based detection system for selective detection of known OP species with low false alarm rates. Requirements such as sensitivity, small size, automatic operation, low cost and ruggedness make the microcantilever sensor approach very attractive for homeland security and environment application. Potential customers for devices to be developed by the company include government agencies such as Homeland Security, Agriculture, EPA, Defense and the Postal Service, as well as similar state agencies. Examples of private customers include farms, water treatment plants, universities and hospitals. [unreadable] [unreadable] [unreadable]